PROC-NAME: DENSD01 Type_1

PURPOSE: To check that the _exptl_crystal_density_diffrn matches the _cell_volume and _chemical_formula_weight values

PROCEDURE:

CALCULATE

DEN = 1.66042 * _chemical_formula_weight * _cell_formula_units_Z / _cell_volume

RD = _exptl_crystal_density_diffrn / DEN

TEST

IF RD 0.9 < > 1.1 issue ALERT A

? ? ? ?? "Alert A The ratio of the submitted crystal density and that calculated from the formula is outside the range 0.90 < > 1.10 "

RD 0.95 < > 1.05 issue ALERT B

? ? ? ?? "Alert B The ratio of the submitted crystal density and that calculated from the formula is outside the range 0.95 < > 1.05 "

RD 0.99 < > 1.01 issue ALERT C

? ? ? ?? "Alert C The ratio of the submitted crystal density and that calculated from the formula is outside the range 0.99 < > 1.01 "

? ? ?? ?The calculated density given in the CIF differs from that calculated using the specified formula weight and the stated number of formula units in the unit cell (Z). Check that (a) you have calculated the density correctly and (b) that _chemical_formula_weight and _cell_formula_units_Z are correctly specified. Remember that _chemical_formula_weight and the calculated density must correspond with the true sum of all elements in all distinct moieties present, including any solvent and all H atoms, and not the contents implied by the model if there are differences due to the omission of a few H atoms or solvent atoms.

? ? ? ? If multiple moieties such as solvent are present, or one of the moieties possesses or is disordered about a crystallographic symmetry element, ensure that the correct ratio of moieties has been allowed for in the calculation of Z and _chemical_formula_weight.

(http://journals.iucr.org/services/cif/checking/DENSD_01.html)

目的：檢查_exptl_crystal_density_diffrn是否與_cell_volume _chemical_formula_weight的值相匹配。

過程：

計(jì)算

DEN = 1.66042 * _chemical_formula_weight * _cell_formula_units_Z / _cell_volume

RD = _exptl_crystal_density_diffrn / DEN

檢查

若RD小于0.9或大于1.1則發(fā)布A級警告

? ? ? ?? "Alert A The ratio of the submitted crystal density and that calculated from the formula is outside the range 0.90 < > 1.10 "

若RD小于0.95或大于1.05則發(fā)布B級警告

? ? ? ?? "Alert B The ratio of the submitted crystal density and that calculated from the formula is outside the range 0.95 < > 1.05 "

若RD小于0.99或大于1.01則發(fā)布C級警告

? ? ? ?? "Alert C The ratio of the submitted crystal density and that calculated from the formula is outside the range 0.99 < > 1.01 "

? ? ? ? CIF中給出的密度計(jì)算值與使用指定分子量和單胞中所含分子單元的數(shù)目(Z)所計(jì)算的密度值不同。請檢查：(a)你已正確計(jì)算該密度值；(b) _chemical_formula_weight和_cell_formula_units_Z指定正確。請記住，_chemical_formula_weight和該密度計(jì)算值必須與所有不同部分中所有元素的真實(shí)總和相對應(yīng)，包括任何溶劑和所有氫原子，若由于刪除了一些氫原子或溶劑原子而存在差異，則不應(yīng)與模型所暗示的內(nèi)容相對應(yīng)。

? ? ? ? 若存在多個組分例如溶劑，或者其中一個組分具有無序或關(guān)于晶體學(xué)對稱元素?zé)o序，則要確保在計(jì)算Z值、化學(xué)式總和(_chemical_formula_sum)以及線性吸收系數(shù)值時各組分的比例為正確且允許的。

例：DENSD01_ALERT_1_A The ratio of the submitted crystal density and that calculated from the formula is outside the range 0.90 <> 1.10

Crystal density given??? = 1.719

Calculated crystal density = 1.422

警告原因：分子式和Z值未填寫正確。

解決策略：在ins里給對分子式和Z值重新精修生成CIF。若使用Olex2軟件，則可填好Z'后精修重新生成CIF即可。